1. Field of the Invention
The present invention relates to determining the class of a vehicle and, more specifically, to a method and an apparatus for determining the class of a vehicle for use in a toll collection system.
2. Background Art
Vehicle-class determining apparatuses used for the collection of tolls generally discriminate between vehicle classes, by collecting various data such as the length, height, and width of a vehicle, the number of axles of the vehicle, the distance between the wheels, and the width of the wheels. The various bits of information are then analyzed and compared to a data base to determine the appropriate vehicle class. Once the vehicle class is determined an appropriate fare is then assessed.
Some techniques for determining the class of a vehicle are shown, for example, in U.S. Pat. No. 5,392,034 to Kuwagaki entitled Vehicle Classification System Using Profile, U.S. Pat. No. 4,789,941 to Nunberg entitled Computerized Vehicle Classification System, U.S. Pat. No. 3,914,733 to Viracola entitled System Including a Pressure Switch for Counting Axles and Classifying Vehicles, U.S. Pat. No. 3,794,966 to Platzman entitled Automatic Vehicle Classification and Ticket Issuing System, U.S. Pat. No. 3,872,283 to Smith entitled Vehicle Identification Method and Apparatus, U.S. Pat. No. 4,493,103 to Yamashita entitled Automatic Toll-Ticket Issuing Apparatus, U.S. Pat. No. 5,528,234 to Mani entitled Traffic Monitoring System for Determining Vehicle Dimensions, Speed, and Class, U.S. Pat. No. 3,927,389 to Neeloff entitled Device for Determining, During Operation, the Category of a Vehicle According to a Pre-Established Group of Categories, U.S. Pat. No. 5,101,200 to Swett entitled Fast Lane Credit Card, and U.S. Pat. No. 3,090,941 to Breese entitled Toll Collecting Device.
Techniques currently in use today lack the ability to detect cars that pass the vehicle class detector apparatus at great speed or closely behind another car. For example, a common device for determining the class of a vehicle is the treadle. Despite the treadle's simple design, employing a contact method, the treadle method generates serious errors. Parts of the treadle must be replaced often and mis-operation may occur since data for determining the class of a vehicle varies depending on the physical contact of the tires. Also, the treadle apparatus, because it uses the contact method, cannot be used in a "rolling" toll collection system since it is hard to install and it cannot accurately sense the vehicle when speeds exceed 60 km/hr. Furthermore, systems that rely on optical sensors, lasers, or transducers can be extremely accurate for collecting vehicle data to determine the class of a vehicle, but they do not generate evidence that can later be used against people that do not pay the toll or that are being prosecuted for another crime, such as car jacking, kidnaping, or car theft.
I believe that it is possible to improve on the current techniques for determining the class of a vehicle while reducing errors due to poor tire contact, lack of evidence generation for future use, high speed rolling toll collection, and cars being closely positioned near each other will improve automated toll collection, lower the overall cost on taxpayers to support local highways, and allow for evidence to be generated at the same time as vehicle dimensions are determined.